Field of the Invention
The present invention relates to compositions having a conjugate of dye and polyethyleneglycol and an additive interacting with the conjugate and contrast agents for photoacoustic imaging having such a composition.
Description of the Related Art
Photoacoustic imaging has recently gained attention as an imaging method for noninvasive diagnosis.
When a subject is irradiated with light, molecules in the subject release heat and the subject is expanded by the released heat. Photoacoustic imaging is a method for obtaining images of the subject by determining the intensity and generation position of acoustic waves generated by the volume expansion of the subject irradiated with light. In photoacoustic imaging, dye can be used as a contrast agent to increase fluorescence and the intensity of acoustic waves from the subject site.
Japanese Patent Application Laid-Open No. 2012-520856 discloses examples of use of conjugates of near-infrared dyes with synthetic polyethyleneglycol polymers having molecular weights in the range of 15 to 45 kDa as optical imaging contrast agents.
Biomacromolecules, 2010, 11(9), pp. 2204-2212 discloses examples of gels formed from mixtures of conjugates of polyethyleneglycol and heparin with cyclodextrin in which BSA (bovine serum albumin) is encapsulated.